BETHESDA, Md. (AP) — Navy officials are taking steps to correct deficiencies that wrongly led to reports of an active shooter last month at Walter Reed National Medical Center outside Washington, two congressmen briefed by Navy officials said Friday.

Reps. C.A. Dutch Ruppersberger and Jamie Raskin of Maryland released a joint statement after their meeting with Navy officials this week.

"After a lengthy discussion, we are satisfied that Naval officials share our concerns and are taking proactive steps to correct deficiencies identified during this event," Ruppersberger and Raskin said.

Messages stating "Exercise Active Shooter" and "Exercise Suspicious Package" were inadvertently sent to nearly 4,000 people on Nov. 27 over an emergency alert system that sends voice call, text and email notifications, the officials said. That led to an 80-minute active shooter lockdown.

It happened after a service member who hadn't been properly trained to use the system intended the messages to go to only a small group in preparation for a future drill. About 15 minutes after the alert was sent, a clerk in the oncology unit reported getting several automated telephone messages stating "active shooter," according to the congressmen.

The clerk reported not hearing the words "exercise" or "drill," and that set in motion pre-planned responses for an active shooter event.

Ruppersberger and Raskin said Naval officials are reevaluating who can authorize users of the alert system and who can release messages over the system. They also are updating training requirements and establishing new controls to prevent a test from triggering an actual response.

Officials also are training and recertifying alert system users on new procedures. The emergency management plan for the Naval Support Activity Bethesda campus is being updated, the congressmen added.

Furthermore, officials are developing means to provide first responders with keys, access cards and blueprints for all installation buildings.

Walter Reed is the nation's largest military hospital and, according to its website, is among the first stops in the continental U.S. for troops wounded in combat.